metropolis vs municipality

metropolis

noun
  • The mother (founding) polis (city state) of a colony. 

  • A large, busy city, especially as the main city in an area or country or as distinguished from surrounding rural areas. 

  • The see of a metropolitan bishop, ranking above its suffragan diocesan bishops. 

  • A generic focus in the distribution of plants or animals. 

municipality

noun
  • The governing body of such a district. 

  • A district with a government that typically encloses no other governed districts; a borough, city, or incorporated town or village. 

  • In Mexico and other Spanish- and Portuguese-speaking countries, second-level administrative divisions that may house one or more cities or towns whose head of government may be called mayors or, in Mexico, municipal presidents. 

How often have the words metropolis and municipality occurred in a corpus of books? (source: Google Ngram Viewer )